Smooth Braking and Turning
#1
I'm working on my overall lack of smoothness but I'm having a hard time visualizing smooth braking and turning. I'm reading Ross Bentley's Professional Racing Techniques and he talks about squeezing the brakes smoothly.
I treat my brake pedal like an on/off switch, I brake late and jam on the brakes and quickly get off them. Now, I recognize that the quick lift off the brake upsets the car, followed by my jerk of the wheel into the turn leaves much to be desired. What are some exercises that I can work on to help me be smoother.
Two feet.
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#2
Has UNK gone over the string to pedals/steering wheel exercise in class yet? If not ask him to, it is easy in person to explain but hard in type. It will come into discussion with traction, but applies to being smooth as well, at least on brake release, that will take care of the 'off'.

I broke myself of the jam on brake habit (the ON) by 'pumping up' the brakes before any hard braking zone. Basically, just before your braking zone starts pump the pedal a few times then on the last pump apply even constant pressure, just like you do when beeding in your new pads (pumping is a good check of your braking system as well). Then on turn in as you start to turn slowly let off the pedal.

Are you smooth with the steering wheel yet? B/c if not pedal control is going to be even harder. Work on one thing at a time. So assuming your steering is smooth this will work, otherwise, work on smooth turn in and turn out. Then work on the braking, then gas. Getting into the gas early and hard should be the last thing you work on.

Once you get this down, THEN work on compressing your braking zones. So if you are doing that now, stop, get the smooth down, then working on doing it all quicker/faster. Stop heel toe as well, just work on smooth steering, then smooth braking, then gas. You can work on heel/toe / smooth gas at the same time since they happen at different times.
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#3
I'll have a hard time putting it into words, but I'll try. I don't like to really stab my brakes. A kinda hit me brake pedal real lightly, and as I feel the car starting to slow down, just push down harder. Now, that may sound like premature braking, and it probably is, but it kept me smooth. The more I did it, the more I "felt" the brakes and the better feel I got from them. Just get out of the "on/off" switch mindset, and just tell yourself to brake slowly and firmly. Practice it around the street as you are coming up on a turn.
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#4
Dave Wrote:I'll have a hard time putting it into words, but I'll try. I don't like to really stab my brakes. A kinda hit me brake pedal real lightly, and as I feel the car starting to slow down, just push down harder. Now, that may sound like premature braking, and it probably is, but it kept me smooth. The more I did it, the more I "felt" the brakes and the better feel I got from them. Just get out of the "on/off" switch mindset, and just tell yourself to brake slowly and firmly. Practice it around the street as you are coming up on a turn.

I can picture being smooth at the faster turns like T3 at Summit Main or T9. But I'm thinking of T1 after a long straight. How can brake "slowly" and heel toe and turn smoothly without plowing the concret wall and ending up on the skid pad.

I can be smooth on the street but at speed, the same rules can't possibly apply can it?
Two feet.
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#5
this sounds really lame, but when i was practicing more actively at smoothness i would hang a key chain (you could use anything with weight) on a long string from my rear-view mirror. i would always try to make the weight hang, without swinging wildly, in one direction or the other. same principle for smooth shifting, up and down.

i've also noticed that my brake pedal smash-tactics differ greatly based on seating position. i'm way more controlled when i'm positioned so that i contact the pedal towards the last 50% of the arc of my foot motion, if my heel is planted on the floorboard and i'm using the ball of my foot to contact the pedal.
2010 Civic Si
2019 4Runner TRD Off-Road
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Past:  03 Xterra SE 4x4  |  05 Impreza 2.5RS  |  99.5 A4 Quattro 1.8T  |  01 Accord EX  |  90 Maxima GXE  |  96 Explorer XLT
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#6
Put it this way... the amount of braking force you can put into a tire varies dependent on the vertical tire loading (ie weight) until the tire reaches its maximum terminal braking force. That's a gross simplification, but it works.

What does that mean? Say you're driving a car with 50/50 weight distribution at constant speed. So you have no weight transfer, ie static weight distribution is what we work with. Let's say our car weighs 1000 pounds, so you have 500 pounds on the front tires. Welp, you plant the brakes, you've only got 500 pounds pressing down on the tire (normal force) and that's also the only thing that keeps the tire from locking. So the tire locks pretty easily.

If we brake lightly and put 60% (600 pounds) of our weight on the front tires, we can brake harder because we have more normal force to resist lockup due to braking force. 70% (700 pounds) on the front tires, we can put in more braking force up until the point we reach maximum tire loading (hypothetical 80% here). So you now have a mathematical relationship between weight distribution and braking force. If you plot braking force against tire loading, you'll see it makes a nice smooth curve. If you want to ride the edge of that curve and brake as hard as you can throughout the braking zone, you will need to brake just like the curve... smooth. Increase braking force as you increase front tire loading. Spiking the brake pedal takes you above the curve, and makes the tire lockup. Instead, ramp your pedal force up smoothly and it will work better.

Efficient brakers brake quickly, but ramp their brake pedal force. If you plotted brake pedal force against time, you'd see there's a nice smooth curve there as well, assuming there's not some reason they're trying to upset the car.

BTW, the first time you come off the brake rapidly after totally using the brakes into a turn... you probably won't want to do it again for a little while. Heh
Chris Perera
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#7
white_2kgt Wrote:I broke myself of the jam on brake habit (the ON) by 'pumping up' the brakes before any hard braking zone.
You don't want to break yourself of that habit! Going from the throttle to initial brake in a straight line is pretty much the only time it's advantageous NOT to be smooth.

Even Randy Pobst agrees!
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#8
good little article there, I hadn't thought of left foot braking straight line just to max accel, but it sure makes sense. I might have to try that next time just to learn. I admit, I ease into the brakes a bit more than needed, and have to brake a bit earlier because of it, but that's a confidence and "need to drive the car home", school thing. The faster you get the weight forward, the more you can brake, and the later you have to do it.
The only thing that stops a bad guy with a van is a good guy with a van
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#9
Eclipsor Wrote:
white_2kgt Wrote:I broke myself of the jam on brake habit (the ON) by 'pumping up' the brakes before any hard braking zone.
You don't want to break yourself of that habit! Going from the throttle to initial brake in a straight line is pretty much the only time it's advantageous NOT to be smooth.

Even Randy Pobst agrees!
interesting article, but physics disagrees with Randy.
I can see the concept being true on a lightweight downforce car, where you have the most grip when you are travelling the fastest, but in a production car with no downforce (lots of lift actually) and a high cG with lots of weight transfer and you have the least amount of grip at high speed just before you press the whoa pedal. You have to ease into the brakes to let the weight transfer to the nose, load the tires and give you more grip. You are still using all the grip available to you as Randy says, but adapting your brakes for the change in grip levels that weight transfer provides.
Ive locked up brakes by going too hard too fast plenty of times.
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#10
Evan Wrote:adapting your brakes for the change in grip levels that weight transfer provides.
Ive locked up brakes by going too hard too fast plenty of times.

Well it's obviously a car limitation thing, so the way you're saying it is correct. You want to hit them as hard and as fast as the car can stand. The softer the car, the slower the weight transfer, but if someone's consiously easing into the brakes, they might be underestimating how fast the weight could transfer if they did it faster/harder.

Physics don't disagree with him though. I think his point is that for any car, if you have to be X smooth in steering and throttle, you should be X/2 smooth on initial braking.
The only thing that stops a bad guy with a van is a good guy with a van
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#11
well he is saying that you shouldnt be smooth on the brakes, which is not the case if you are using your weight transfer. hitting them hard like he says is not waiting for the car to weight the front. Doing so creates a natural progressively smooth application of brakes. We arent talking a long time here, probably 1/2 of a second, but its still a noticable difference between the slamming brake pedal that he describes.

this wouldnt be too hard to demonstrate with an accelerometer DAQ
SM #55 | 06 Titan | 12 Focus | 06 Exige | 14 CX-5
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#12
Notice the word's ramp up in braking, and how he talks about locking up. Yes on a car with shit loads of downforce you can do that.

For Example: On my car with my pirellis on I would slam on the brakes and the rear end would become wayyyyyy too light (production cars dont generate much downforce). and actually would lock up the rears, because it was so light (and I have a lot of weight transfer to the front). This would cajuse the back end to scoot out either way which is incredibly dangerous.


This "theory" is a good one, provided the car is a professional car with shit loads of downforce and huge slicks front and rear, however it is dangerous to follow the advice of how a guy drive's his car with shit loads more power, brakes, grip, downforce, where he cn pull a LOT of shit that we can't even imagine doing in our vehicles.
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#13
Good discussion, guys. I'm struggling with this squeezing on the brakes thing. I can't get the right balance between getting on them smoothly yet quickly and calculating the proper distance. I either scrub too much speed off or come in too hot. It seems like in my car at least, if I get on the brakes hard immediately as late as possible in the shortest time possible, I get through turns faster and seemingly more control. Some of the younger instructors are okay with it while some of the older guys are telling me it's a no-no.

What steps did you guys use to improve your braking?
Two feet.
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#14
Yes, the technique Randy described is best for a car with high downforce and a stiff suspension setup. I'm hoping that's what we all aspire to drive on the track. Even production cars can be setup like racecars. Isn't that the goal?

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#15
D_Eclipse9916 Wrote:provided the car is a professional car

that may be true, but he clearly applies his technique even in WC. Those cars do NOT have much downforce, and run street legal tires. Sure, they're stiff, and set up correctly, but this isn't like a formula-car-only idea here.
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#16
Andy Wrote:What steps did you guys use to improve your braking?
Trail braking is a very useful skill to learn. Learning to smoothly release the brake pedal is also critical. Here's an article describing dynamic brake release.

Quote:GRANT RILEY

Born: Los Gatos, CA May 14, 1973

I got into racing late. I was around 22 years old and working construction in Phoenix when I finally realized that I could fulfill my dream at Skip Barber Racing School. Basically, I quit my job, attended my three day and went on to race the Western Race series. Two seasons, several wins, 5 million laps, a couple of big ones and a 80 shifter go-kart later, I moved up to the Star Mazda series with support from my family, family friends and some help from the race team.

I spent another two seasons in Mazda and in the second year just missed the championship after winning the most races. In 1999 I was one of ten drivers invited to test for the then recently formed ÔÇ£Kart to CartÔÇØ scholarship program in the Toyota Atlantic series. I was selected to drive and contested the championship in 2000 and again 2001 with Lynx racing. I was fortunate to sit on pole, set a track record and reached the podium a few times however the racing gods kept me from a race win in Atlantic.

During my career IÔÇÖve driven and raced Sports cars, Prototypes and formula cars of all shapes and sizes with my personal favorite being a Porsche 962 I was lucky enough to race at Daytona. IÔÇÖm still actively involved in racing and last year reunited with my old buddies in the Toyota Atlantic series for a single race at the San Jose Grand Prix.

The Dynamic Brake Release

For those of you who work with me on a regular basis, you know that I am a stickler for a smooth brake release, and smoothness in general. In this article, I will talk about brake release and in the next, if invited back, IÔÇÖll talk about combining this with the general smoothness principle.

Some mistake being smooth with being slow. This is not the case at all. Being smooth means using specific techniques to keep your car balanced at all times. Think of the tight- rope walker. His actions are not fast, but completely deliberate. If any of his motions are hurried, he will loose his balance. The same applies with your racecar. To go fast, you must keep your racecar on the tight rope. One hasty or reactionary move will cause the car to loose its balance.

99% of the time when a novice driver spins his car it has nothing to do with his ÔÇ£speedÔÇØ. It has everything to do with his speed relative to his footwork and by ÔÇ£footworkÔÇØ I mean brake release. The first thing that happens when a driver goes, at what he/she perceives as, ÔÇ£fastÔÇØ is the inputs in the car happen ÔÇ£fastÔÇØ. The driver becomes reactionary and relies on his reflexes and car control to keep the car on the track. The driver has become a passenger.

In reality, the opposite needs to occur. The faster you go, the slower and thus more deliberate you need to be with your inputs.

So what does all this mean? Brake release is dynamic! If driving at Laguna Seca, your brake release is and should be different for turn 2 than it is for turn 3. Different again for turn 5 than turn 6. And still different if your passing going into turn 2 verses having broke too early. Why? Because the rate at which you release the brake pedal will have a direct effect on what the car does as you turn in and, in trail braking corners, what the car does mid corner.

To take this one step further. What makes a great driver consistent is not necessarily their brake points, line, down shifts, etc. Those are there in place very early on. Consistency comes from the ability to sense speed in the brake zone and adjust the brake release accordingly so as to arrive at the turn in point with the same speed every lap.

So lets take a step back for a moment and assume that most of you reading this have not reached your full ÔÇ£potentialÔÇØ. You have yet to fully develop those crucial speed sensing skills and are frustrated and become even more frustrated when you come in from a session only to have an instructor tell you, ÔÇ£your over-slowing turn 5ÔÇØ. How does dynamic brake release apply to you? IÔÇÖll tell you.

Close your eyes and visualize your average approach to turn 5. Where do you brake? Where do you down shift? Where do you turn in? Got it? Ok. Take it a layer deeper. After you do your down shift, what does that right foot do? Does it stay there on that 10 pedal until youÔÇÖve reached your corner entry speed then bleed off at or just before the turn in? Yes? Read on and take it a layer deeper.

At the precise moment when you are happy with your entry speed and the foot begins to come off the brake pedal what happens? Well, if you simply ÔÇ£side stepÔÇØ or ÔÇ£snapÔÇØ off the brake pedal the car will slide at turn in, rite? So instead you concentrate on the smooth brake release, turn in, go to power and exit only to find out later you are still over-slowing.

Take it one more layer deeper. During the time it takes for you to ÔÇ£bleedÔÇØ or smoothly release the pedal the car is still slowing. The root of the problem is you havenÔÇÖt started your brake release soon enough. If you wait to start the release until you are comfortable with your speed, youÔÇÖve over-slowed. You need to begin releasing the pedal sooner and that generally means releasing slower. The trick is to isolate that microsecond when you are comfortable with your entry speed and begin releasing the pedal a heartbeat before that. Even though the foot will naturally come off slower your entry speed will be higher and your racecar will be happier as you turn in.

To put this visually, here are two examples with the numbers representing brake pressure.

The over-slow style: 10-10-10-downshift-10-10-10-10-7-5-3-1-0 (fairly smooth but too much 10)
The entry speed style: 10-10-10-downshift-10-9-8-7-6-5-4-3-2-1-0 (smoother release/more entry speed)

Looking at these examples you might say, ÔÇ£why not just brake later?ÔÇØ The answer is two fold. One, there is a point of diminishing returns with your brake point. The later you go, the less time you have to get everything done which equals a choppy release. And two, when learning this technique, the later you go, the less time you have to get everything done, which equals fear, panic and yes, choppy release possibly resulting in a spin and the self belief that you can go no faster. You do however; have to pick a brake point that is late. Just not Juan Pablo Montoya, late.

As stated before, I will get more into the smoothness principle and dynamic brake release later. For now, here is a drill to practice smooth brake release and speed sensing on the street. This drill comes with the caveat of ÔÇ£donÔÇÖt be a jerkÔÇØ. Do this drill at no more than the posted speed limit and without traffic hazards nearby.

Find a stop sign or two on your everyday commute. Your everyday driving has you coasting up to the stop sign where you gradually apply brake pressure. First of all eliminate the coasting and continue at the posted speed limit. Find your brake point and brake initially at the hardest pressure you will achieve. (On the street this may only be a 4 pedal) Once you get to your max pressure, try to sense your slowing so as you can smoothly release pressure all the way until you come to a complete stop. If you have to add brake pressure in the brake zone, youÔÇÖve released too fast. If done correctly, you may have to look out the window to see if the car is still moving when you get to the limit line.

The visual representation goes like this.

4 - 4 - 3.5 - 3 - 2.5 - 2 - 1.5 - 1 - .9 - .8 - .7 - .6 - .5 - .4 - .3 - .2 - .1 - 0

This is the same technique that you employ when trying to get more entry speed in 5 or trail braking into 2 (at a much higher speed and pressure, of course). It is also similar to the chauffer stop that many of you do every day with the family in the car although it differs in a couple of ways. You are eliminating the coasting and your initial brake pressure is the hardest you will ever achieve in that brake zone. Again, donÔÇÖt be a jerk and donÔÇÖt do this with traffic behind you, as ÔÇ£old low eyesÔÇØ wonÔÇÖt see it coming.

In the practice what you preach file. I started this technique when I was transitioning from right to left foot braking. And is a technique I still do today when I am preparing to drive a race car or just want to shake off the cobwebs. It will train the small muscles in your foot and ankle how to release the pedal properly and you may find that just by changing where you place your heel on the floorboard it may make a world of difference to your smoothness. All in all, good things.

Good Luck and see you at the track

Grant Ryley
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#17
Eclipsor Wrote:Trail braking is a very useful skill to learn.

Its a useful skill to have in your toolbox, but its not essential - and the better your car setup is, the less you have to do it, IMHO, unless you are limited by the rules to things like stock springs/swaybars.
(09-25-2019, 03:18 PM)V1GiLaNtE Wrote: I think you need to see a mental health professional.
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#18
.RJ Wrote:Its a useful skill to have in your toolbox, but its not essential - and the better your car setup is, the less you have to do it, IMHO, unless you are limited by the rules to things like stock springs/swaybars.
Thank you for agreeing with me. Big Grin

Now, why do you feel that you have to trail brake less the better your car is setup? From my experiences, I've found that a lot of people seem to think the main reason for trail braking is to brake deeper into the corner. In reality, trail braking is mostly used to rotate the car towards the apex. Whether or not trail braking should be used is most often determined by the corner, not the setup of the car.
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#19
Eclipsor Wrote:Now, why do you feel that you have to trail brake less the better your car is setup?

Because if I trail brake with 1000+ lb rear springs the car spins Wink
(09-25-2019, 03:18 PM)V1GiLaNtE Wrote: I think you need to see a mental health professional.
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#20
.RJ Wrote:Because if I trail brake with 1000+ lb rear springs the car spins Wink
Heh, yeah... like I said up there... rotation is the goal. Just be a bit more smooth.

Quote:Trail braking helps you rotate the car into a corner by controlling the transfer of weight onto the front tires, giving them more stick, and thus compensating for any understeering tendency the car would otherwise have.

The alternative is: do all of your braking in a straight line, then release the brakes entirely, then turn in. The trouble with this technique is that when you release the brakes, weight - and therefore stick - will be removed from the front tires, just when you need them to be loaded enough to turn the car into the corner. So - unless the car is set up to be driven like this - it will understeer away from the corner. This is typical behavior for 'street' (aka massively understeering) cars that have been adapted for racing.

On the other hand, a 'proper' race car will probably oversteer if you don't trail brake. If you turn into a corner with your feet off both brake and throttle, the front tires will have all their traction budget available for turning while the back wheels will be doing some (engine) braking. Net result: oversteer. Application of the brakes settles down the oversteer by substituting a proportionately balanced loss of steering traction (because the brakes are biased towards the front). In fact, you use the brake pressure to control the rate at which the car rotates into the corner.

How much trail braking you do at a particular corner - i.e. what percentage of the corner is taken under braking - depends on the angle of the corner. For a 60┬░ corner, you'd typically only trail for a few percent of the corner, for a 90┬░ corner, you'd typically trail brake for maybe 25% of the corner, and for a bigger corner, you could do it for up to 50% of the corner. You are aiming to trail off the brakes until they are released completely at or before the throttle application point (which typically occurs somewhere before the geometric apex).

Another way of looking at trail braking is: what you're doing is braking so late for a corner, that you're never going to make it if you carry on in a straight line. In order just to stay on the track, you have to release a little of the pressure on the brake pedal and bend the car into the corner, just to give yourself a little more road - enough extra road to finish the braking. If you find that you've finished braking before the throttle application point in these corners, then you didn't brake late enough. (BTW, if the car won't turn in when you release a little brake pressure, then you probably need to reduce the front brake bias; likewise, if the car swaps ends when you turn in, add some front brake bias).
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